1. Field of the Invention
The present invention relates to a monitor system for detecting and stopping vehicles traveling the wrong way on a portion of a road designated for a particular direction. The monitor system more particularly includes transmitter, receiver and control means within the vehicle and includes one or more reflectors mounted on or near the road structure.
2. Description of the Prior Art
Collisions involving motor vehicles have catastrophic consequences, and automatic systems for reducing speed or otherwise controlling a vehicle have long been known. These systems typically rely upon a system of reflected energy being received by a vehicle that is speeding, or excessively close to another vehicle or to an oncoming vehicle, the reception thereof activating controls.
The problem of a motor vehicle being driven the wrong way on a one-way lane or road is infrequently encountered, but the consequences are sufficiently severe that automatic intervention is warranted. In U.S. Pat. No. 3,559,756, issued on Feb. 2, 1971 to Noel M. Torres, a detection system is presented that applies the brakes of a vehicle detected going the wrong way. Torres provides a transmitter, receiver and controlling apparatus aboard a vehicle, and appropriate reflectors built into the road structure. The controlling apparatus includes a pulse counter. The rate of reflected energy is used to make control decisions, such as possible adjustment of the throttle, and to control the degree of corrective adjustment made.
There are a number of practical aspects which are not addressed by Torres that render control of the vehicle tenuous. The lack of an alarm indicator may render the driver confused, the driver then possibly responding inappropriately. One example is that if the driver fails to recognize the problem, he or she may attempt to increase speed, overriding the throttle adjustment and pitting the engine against the brakes. Since this will typically occur on a curved ramp, loss of vehicle control may result.
A second example is the predetermined safe minimum distance to the reflector that triggers brake actuation. Torres refers to such a distance, but no procedure for determining the actual value of such a distance is presented. This distance may vary with the weather, traffic density and other conditions to which the detection system may not respond or adjust. Torres further assumes that the apparatus will incorporate a minimum signal threshold to preclude frequent false responses. Setting such a minimum value, and adjusting it for different conditions, may prove difficult to accomplish in practice.
Similarly, brake override of the speed control is subject to calibration problems. This could be true due to varying radius of road curvature of different ramps or variations in ascending or descending grades, different speeds being safe on different ramps. A vehicle being calibrated to a single value is susceptible to being inappropriately calibrated for any given ramp.
U.S. Pat. No. 3,112,004, issued to Arthur W. Neaville on Nov. 26, 1963, discloses a vehicle disablement system which shuts down the vehicle engine, restart being enabled after a predetermined time delay.
U.S. Pat. No. 2,896,089, issued to Ludwig Wesch on Jul. 21, 1959, discloses a vehicle warning system which detects proximity of an obstacle, and which provides a visible or audible alarm to the vehicle operator.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.